1. Field of the Invention
The present invention related to air purification systems and related method and more particularly to an air purification system of the type that enhances filtration by subjecting airborne contaminants to complex electrical fields.
2. Discussion of Related Art
Air purification systems of the type under consideration include a fixed output power generator that produces a high voltage (HV) direct current and/or a high frequency (HF) alternating current. The HV and HF output from the power generator is fed to separate electrodes. In large installations, electrodes are installed in an air handling plenum, between the mixing box and cooling coils. In operation, the HV and HF outputs generate a complex electrical field at the electrode assembly. All of the air passing through the space being conditioned by the system, passes through this complex electrical excitation field during primary and secondary air cycling. The submicron particles tend to collide and adhere to each other and more rapidly increase their mass. They are then more easily carried by the system air flow back through the return to be captured in the filters or exhausted from the building. The system thereby enhances filtration and removal of airborne particles and gasses thus, reducing contaminants in a conditioned space.
As a result, air purification systems of this type save energy dollars by reducing the need for large amounts of outside air, save initial investment dollars by reducing heating and cooling equipment requirements, saves costs in the day-to-day cleaning of the conditioned space and the cleaning and maintenance of the air handling equipment. Air purification systems of this type also control the contaminants such as offensive dust, smoke and odor and thereby increase human efficiency by restoring fresh, clean air to the interior environment in which we live, work and breathe.
These systems operate effectively with no noise in the conditioned space. They are also out of sight, thus rendering it difficult for anyone to immediately detect interruption in the operation of the purification by the system. To handle this problem, present power generators are equipped with an indicator, such as a light emitting diode, to indicate if the generator itself is turned on and functioning electrically.
But in air purification systems of this type, in which contaminants are subjected to a complex electrical field as part of the purification process, many ambient conditions, system parameters and type of contaminants influence the efficiency and effectiveness of the system. Thus, although the failure of the fixed output power generator itself can be detected, the effective operation of other components of the system and relevant ambient conditions cannot be readily detected. As a consequence, the air purification system can be rendered ineffective; and such can only be detected by the gradual recontamination of the air. During this time, the space reverts to the conditions which prevailed prior to the utilization of the air purification system. Further, inasmuch as a period of time is required before an air purification system of this type can reduce the contaminants to the optimum level, particularly in large installations, any malfunctioning of a part of the system or change in operating conditions may create an impure air quality condition that takes several hours or days to be removed completely, even after such malfunctioning has been noticed and remedied.
It has also been determined, that certain combinations of electrical field characteristics work better than others in removing certain types of contaminates from the air. Thus, it is desirable to be able to pre-select electrical field characteristics and independently of each other to maximize the air purification rate for a particular application. Once the selection has been made, it is then desirable that such characteristics be maintained.
Each optimum electrical field characteristic should be maintained even though the electrode screen assembly itself becomes contaminated or is otherwise subjected to conditions that would affect the electrical characteristics on the electrodes and the associated electrical field.